Proust revisited: odours as triggers of aversive memories.

According to the Proust phenomenon, olfactory memory triggers are more evocative than other-modality triggers resulting in more emotional and detailed memories. An experimental paradigm was used to investigate this in aversive memories, similar to those experienced by patients with posttraumatic stress disorder. Seventy healthy participants watched an aversive film, while simultaneously being exposed to olfactory, auditory and visual triggers, which were matched on intensity, valence, arousal and salience. During a second session one week later, participants were randomly exposed to one of the three triggers, and asked to think back about the film and to rate the resulting memory. Results revealed that odour-evoked memories of aversive events were more detailed, unpleasant and arousing than memories evoked by auditory, but not visual, triggers.